Experimental results and mathematical modelling of an autotrophic and heterotrophic biofilm in a sand filter treating landfill leachate and municipal wastewater

Wichern, Marc; Lindenblatt, C.; Lübken, Manfred; Horn, Harald

doi:10.1016/j.watres.2008.05.031

Cited by 23 publications

(11 citation statements)

References 31 publications

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“…Filter material was characterized with respect to specific surface area, porosity, grain size distribution, HRT as well as for chemical composition (Tables S1-S3). The surface area of biochar (500 m²•g −1 ) was determined according to DIN ISO 9277, while the surface area of sand (<0.01 m²•g −1 ) was calculated assuming a spherical shape of the particles according to Wichern et al 48 . Elemental composition of biochar (C, N, H, O) was measured in triplicates according to DIN 51732, using a Vario EL Cube elemental analyzer (Elementar Analysensysteme GmbH, Langenselbold, Germany).…”

Section: Methodsmentioning

confidence: 99%

Slow sand filtration of raw wastewater using biochar as an alternative filtration media

Kaetzl

Lübken

Nettmann

et al. 2020

Sci Rep

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The efficiency of anaerobic biofilters (AnBF) as low-cost wastewater treatment systems was investigated. Miscanthus-biochar was used as filtration media and compared with sand as a common reference material. Raw sewage from a municipal wastewater treatment plant was stored in a sedimentation tank for two days to allow pre-settlement of wastewater particles. Subsequently, wastewater was treated by AnBFs at 22 °C room temperature at a hydraulic loading rate of 0.05 m•h −1 with an empty bed contact time of 14.4 h and a mean organic loading rate of 509 ± 173 g coD •m −3 •d −1 . Mean removal of chemical oxygen demand (COD) of biochar filters was with 74 ± 18% significantly higher than of sand filters (61 ± 12%). In contrast to sand filters with a mean reduction of 1.18 ± 0.31 log-units, E. coli removal through biochar was with 1.35 ± 0.27 log-units significantly higher and increased with experimental time. Main removal took place within the schmutzdecke, a biologically active dirt layer that develops simultaneously on the surface of filter beds. Since the E. coli contamination of both filter materials was equal, the higher removal efficiency of biochar filters is probably a result of an improved biodegradation within deeper zones of the filter bed. Overall, performance of biochar filters was better or equal compared to sand and have thus demonstrated the suitability of Miscanthus-biochar as filter media for wastewater treatment.www.nature.com/scientificreports www.nature.com/scientificreports/ degradation during storage time. To avoid sedimentation, the storage reservoir was continuously stirred (IKA RW 10 R, IKA-Werke, Staufen, Germany) and renewed every two days.The filters were fed by peristaltic pumps (Watson Marlow 205 S and Watson Marlow 323 S; Falmouth, United Kingdom) with a constant HLR of 0.05 m•h −1 . The mean organic surface load was 366 ± 125 g COD •m −2 •d −1 and 111 ± 37 g TOC •m −2 •d −1 , respectively. This resulted in a mean OLR of 509 ± 173 g COD •m −3 •d −1 and 154 ± 52 g TOC •m −3 •d −1 (Table 1). The experiment was performed at constant room temperature (22 ± 1 °C) with an empty bed contact time of 14.4 h.Sampling. Before the first sampling filters were operated with wastewater for six days. Samples of influent and effluent were taken in sterile 50 mL tubes and tested immediately for FIB E. coli and enterococci, temperature, pH, EC and turbidity as well as stored for further physico-chemical analysis, namely NH 4 -N, P tot , COD and TOC at −20 °C. To develop a removal profile over filter depth, water samples were taken at the sampling ports (b), (c), (e) and the effluent (f, Fig. 6) 50 days after filter activation and analyzed for FIB concentrations.After 70 days, one sand and one biochar filter have been dismantled to sample filter material at the filter depths 0-5 cm (direct below the schmutzdecke), 10-15 cm, 20-25 cm and 40-45 cm. Filter material was tested for FIB and prepared for scanning electron microscope (SEM) and confocal laser scanning microscope (cLSM) analysis. Scientific RepoRtS |(2...

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Section: Methodsmentioning

confidence: 99%

Slow sand filtration of raw wastewater using biochar as an alternative filtration media

Kaetzl

Lübken

Nettmann

et al. 2020

Sci Rep

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“…To determine the surface area of biochar and woodchips, a BET (Brunner Emmet Teller) multipoint adsorption isotherm with N 2 as adsorbent was prepared in a surface analyser at 77 K (Autosorb 6, Quantachrome Instruments, Boynton Beach, FL, USA) according to DIN ISO 9277. The surface area of quartz gravel was calculated according to Wichern et al [37]. The mean ZP of gravel was −28.4 ± 1.3 mV (variation range indicates standard deviation)-slightly more negative than that of biochar (−20.8 ± 0.8 mV) and woodchips (−13.1 ± 1.6 mV).…”

Section: Filter Materialsmentioning

confidence: 99%

Efficient Low-Cost Anaerobic Treatment of Wastewater Using Biochar and Woodchip Filters

Kaetzl

Lübken

Gehring

et al. 2018

Water

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Access to improved sanitation is often lacking in many low-income countries, and approximately 90% of the sewage is discharged without treatment into receiving water bodies. The aim of this study was the development and evaluation of an efficient low-cost wastewater treatment system for developing countries. Biochar and woodchips, potential locally available and inexpensive materials, were used for anaerobic wastewater filtration and their suitability evaluated in comparison to gravel as a common reference material. Filters were fed with raw sewage from a municipal full-scale wastewater treatment plant in Germany at 22 • C room temperature with a hydraulic loading rate (HLR) of 0.05 m•h −1. This resulted in a mean organic loading rate (OLR) of 252 g COD •m −3 •d −1 and a mean organic surface load of 456 g COD •m −2 •d −1. To determine the influence of different filter materials, the removal efficiency of chemical oxygen demand (COD), total organic carbon (TOC), turbidity, and faecal indicator bacteria (FIB) E. coli and enterococci were tested. It was found that COD (up to 90%), TOC (up to 80%), FIB (up to 1.7 log 10-units), and turbidity (effluent turbidity below 35 NTU) could be significantly reduced. The findings of this study demonstrate the potential of anaerobic filters (AFs) for wastewater treatment in low-income countries to reduce water pollution and comprehensively improve water quality. The performance of biochar filters was significantly better over the entire experiment compared to woodchip and gravel filters with respect to COD, TOC, turbidity, and FIB removal, indicating the superior properties of biochar for wastewater treatment.

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“…This must be considered to explain or modelize hydraulical behavior as well as degradative capacities of such filters. cannot thus rely solely upon the current hypothesis of fixed biofilm accumulation on the media superficy [27].…”

Section: Resultsmentioning

confidence: 95%

Aerobic Granules Formation in Dual-Layer Percolating Filters

Drakides¹

2012

J Civil Environment Engg

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Aerobic spherical granules were observed in zeolitic dual-layer intermittent percolating filters treating domestic septic tank effluent. The diameter of the granules ranged from 0.05 to 0.5 mm and when they predominate in the biofilms the mean SVI value was of 54 ml g-1 instead of 232 ml g-1 when they were absent. Flow behavior in these filters was characterized by the dimensionless Reynolds number. The values obtained (40

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Experimental results and mathematical modelling of an autotrophic and heterotrophic biofilm in a sand filter treating landfill leachate and municipal wastewater

Cited by 23 publications

References 31 publications

Slow sand filtration of raw wastewater using biochar as an alternative filtration media

Slow sand filtration of raw wastewater using biochar as an alternative filtration media

Efficient Low-Cost Anaerobic Treatment of Wastewater Using Biochar and Woodchip Filters

Aerobic Granules Formation in Dual-Layer Percolating Filters

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